1. Field of the Invention
The invention is directed to the field of coupling means for elongate members.
2. Description of the Prior Art
A typical example of a prior art coupling device employing ring-like elements is disclosed in U.S. Pat. No. 2,246,750 issued to H. J. Murphy on June 24, 1941. This device comprises a series of D-shaped openings formed or stamped in an elongate length of flat material which is then bent into an undulating element arranged so that the central axes of the openings are inclined to one another to provide a locking fit about an elongate member inserted within the openings. The device is thus designed to provide an in-line coupling between two elongate members. Such devices, however, provide little resistance to bending and distortion and thus have often been found lacking in the necessary strength or rigidity required to provide a tight, secure coupling between such elongate members. Other devices for coupling elongate members include sleeve-like elements which are provided with locking screws or the like designed to bite into the elongate member to provide the necessary coupling. Such devices, although tending to serve a limited purpose, are relatively expensive to manufacture, comprise a plurality of parts, require additional time to affect the locking action, and are subject to corrosion or rusting of the threaded parts after a period of use. In many cases such devices are used to join electrical conduit wherein the ground connection between two conduit ends is provided by a path through the locking screws and the body of the coupling sleeve. Such grounding path may be rendered either partially or totally ineffective in the event of such rust or corrosion, thus causing a faulty and possibly dangerous condition.